div {
    width: 512px;
    margin: auto;
    position: relative;
}

img {
    width: 512px;
    height: 288px;
    vertical-align: bottom;
}

.dote {
    position: absolute;
    bottom: 0;
    height: 20px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.dote>span {
    display: inline-block;
    height: 10px;
    width: 10px;
    border-radius: 50%;
    margin: 2px;
}
span[class^="jian"]{
    position: absolute;
    top:50%;
    margin-top: -50%;
    display: inline-block;
    height: 50px;
    width: 50px;
    border-radius: 50%;
    margin: 2px;
    background-color: rgba(255, 255, 255, 0.1);
    text-align: center;
    line-height: 50px;
    color: white;
}
.jianleft{
    left: 0;
}
.jianright{
    right: 0;
}
